1. Field of the Invention
The invention relates to a method for producing an optical component, to the optical component produced according to the method and to devices comprising such components.
2. Description of Related Art
Optical components, which are based on the guiding and manipulation of light by structures such as waveguides and gratings, are already well known for example in the fields of sensors and telecommunications.
Beam shaping refractive devices are furthermore used, for example in imaging or illuminating systems, and especially for beam shaping of the light emitted by semiconductor lasers.
Devices for beam shaping of the light from high-power lasers are conventionally constructed in: an elaborate way with multilens refractive systems (for example lens and/or prism arrays), see for example DE 195 00 513 or DE 198 46 532 and EP 0 961 152. These optics are used to carry out beam shaping, in particular circularization of the elliptical beam cone between the so-called fast and slow axes.
Furthermore, PCT/EP02/03283 proposes linear prism fields for correcting the light emerging from a laser array. In this case, respectively different tilted prisms are intended to compensate for a lateral offset of individual lasers, known as a “smile”, in which the respective light exit surface of the individual laser lies not on a straight line but on a curved line.
In general, however, lens and prism arrays are difficult to manufacture and adjust, and have step-shaped lateral surfaces between the respective prisms, which are detrimental to the light propagation owing to reflection. Further multiple prism arrangements are also known from U.S. Pat. No. 6,421,178 B1.
WO 00/19248 describes a biconcave micro-cylinder lens system, in which at least two aspherical lenses are produced with high accuracy.
It is known from the standard textbook “High-Power Diode Lasers” by R. Diehl, Springer (2000) that for exact fast axis collimation (residual divergence <5 mrad) of diode laser emitters or emitter arrays by means of purely refractive optics, it is necessary to use materials of high refractive index (generally >1.7) in conjunction with aspherical surfaces. Disadvantages of such systems are not only the high outlay for producing the aspherical surfaces to be adjusted relative to each other, but also the difficulty of exact mounting, for example in exact alignment with a stationary light source.
In many technical application fields, an increasing need for high-performance optical systems is developing. The spectrum comprises, for example, laser technology, printing technology, solar technology, biochemistry, sensors, adaptive optical systems, optical computers, optical memory systems, digital cameras, two- and three-dimensional image reproduction, lithography and measuring technology.
In order to compensate for optical errors, or in order to produce particular beam profiles or complicated geometries, optical systems having a plurality of optical components are often necessary.
The production of individual optical components by shaping glass material is known, for example, from U.S. Pat. Nos. 4,734,118, 4,854,958 or 4,969,944. In order to join two optical components together to form an optical system, they are typically bonded to each other by a suitable adhesive layer or mounted in a common frame.
It is known from JP 60205402 A, for example, to connect a glass optical component to a plastic optical component by means of an adhesive layer. It is furthermore known, for example from JP 07056006 A, to apply a colored plastic layer onto a glass optical component.
The bonding of two glass optical components and the application of plastic onto glass generally require cost-intensive reprocessing, for example in the form of fine polishing or edge grinding.
It is furthermore known from DE 43 38 969 C2 to apply complex diffractive structures onto the surface of an optical component by etching. This method, however, requires elaborate process steps and therefore entails high costs.
To a certain extent, bi- or multifunctional components can be produced by corresponding diffractive structures in fibers; for example, suitably doped silica glass (SiO2) (for example Ge-doped) is already used for the production of Bragg gratings as de/multiplexers (wavelength filtering) or sensors in fibers. An inhomogeneous defect distribution, which leads to refractive index changes by changing the absorption coefficient, is in this case generated in the Ge-doped glass by UV irradiation.
It is furthermore known that structures can be generated in glass by irradiating various glasses with suitable high-energy pulses (fs pulses). For example, positive refractive index changes in the range of 10−2 are generated by the fs scribing of Ge-doped SiO2 glass (K. Hirao et al., J. Non-Cryst. Solids 235, pp. 31-35, 1998). Similar index changes have also been observed in borosilicates, sulfide and lead glasses (Corning WO 01/44871, PCT/US00/20651). By suitably adjusting the pulse energy and scribing rate, it is in this case possible to produce refractive index changes without physical damage to the glass (ablation, micro-cracks).